MONTAGUE, Calif.—Officials say two men were killed when a small homemade plane crashed in a field in Northern California near the Oregon state line.

Federal Aviation Administration spokesman Ian Gregor tells The Associated Press the single-engine homebuilt Glasair II plane crashed in the town of Montague under unknown circumstances on Wednesday morning.

Siskiyou County sheriff's spokeswoman Allison Giannini tells the Redding Record Searchlight (bit.ly/13EuM1f) that deputies responded to the crash at a property in the Big Springs area and found two men dead—55-year-old Lloyd Rugg of Montague and 77-year-old Larry Graves of Yreka (wye-REE'-kuh).

The National Transportation Safety Board is investigating the crash and will try to determine a cause.